For a beginner they are pretty good, they evolve over the course, especially when you start using gimp...

You want to create a background that fits with the subject image and try and merge it with said image, because other wise it looks out of place in the case of this flamedramon one....you may want to also download a few more text types and try experimenting with effects on the text as well as using one that relates to the image, you may also want to keep the same type of text in a sig and not change it to different types for different words...on the whole these are pretty good....(more so when you get into gimp) just keep practicing and i can see you going a lot further.